Except that qwerty_asdf wasn't referring to a /24 subnet, (s)he was talking about one of the three address spaces defined in RFC 1918 and described thusly:
"Note that (in pre-CIDR notation) the first block is nothing but a single class A network number, while the second block is a set of 16 contiguous class B network numbers, and third block is a set of 256 contiguous class C network numbers."
So it is common for crusty old network engineers and sysadmins to refer to 192.168/16 as "the class C" private block, even when they understand that you can subnet it however you'd like.
"Note that (in pre-CIDR notation) the first block is nothing but a single class A network number, while the second block is a set of 16 contiguous class B network numbers, and third block is a set of 256 contiguous class C network numbers."
So it is common for crusty old network engineers and sysadmins to refer to 192.168/16 as "the class C" private block, even when they understand that you can subnet it however you'd like.